In general, object sensors are widely used with a wide variety of apparatuses including apparatuses for identifying irregular surfaces and materials of coins in coin-handling apparatuses, such as automatic vending machines, automatic ticket vending machines, ATMs, and motor rotation drive control apparatuses. Generally, conventional object sensors of the aforementioned type have an eddy-current type configuration as shown in FIG. 10 for example. Electric current is applied to a coil 200 wound on a rod-shaped core body 100 whereby to generate a detecting magnetic flux φr. In a magnetic field formed by the detecting magnetic flux φr, a detection target object 300 and the core body 100 are moved relative to each other. At this event, variations take place in the magnitude of eddy currents generated by the detection target object 300 in correspondence with variations of the distance between the two, and magnetic resistance is varied. The variation amount is taken as being the amount of inductance variations thereby to obtain detection outputs, as shown in FIG. 11.
However, in the conventional object sensor, a direct current (DC) resistance part is included the magnetic resistance variations with air being interposed between the core body 100 and the detection target object 300. Accordingly, finally detected outputs are correlated with impedance variations. Consequently, in the conventional object sensor, the detection output sensitivity cannot yet be said as having reached a sufficient level. In addition, there is a problem in that high temperature characteristics cannot be obtained because of influences of factors such as temperature-caused variations in magnetic permeability of a DC resistor part.
In addition, the magnetic resistance variations in the air between the detection target object 300 and the core body 100 are proportional to the square of the distance, so that the linearity of the detection outputs is not high. Further, as is shown in FIG. 12, variations in three dimensional magnetic flux φr are utilized to increase the variation amount thereof, so that the overall apparatus is prone to be enlarged in size. An additional problem is that since the impedance varies following the change in the length between a sensor amplifier and a cable, the amplifier should be tuned.
As another general practice, in the fields of apparatuses such as ATMs, automatic vending machines, and automatic ticket vending machines, there are widely used card readers of the type that performs recording/reproduction of specific information on an information recording section of each of various type cards. In addition, many cases are observed in which an inlet sensor for detecting, for example, the genuineness and the obverse and reverse sides of a card inserted in the apparatus mainbody is mounted in a portion immediately after or near a card insertion slot. The inlet sensor is used to perform sensing for the information recording section of the card inserted in the apparatus mainbody whereby to detect whether a correct card is inserted or whether the obverse and reverse sides of the card are not opposite even when the correct card is inserted. In this case, when an incorrect card is detected, the card is held in the state where a shutter disposed immediately after the inlet sensor or on the downstream side thereof is kept closed thereby to prevent, for example, an illegal action.
Further, in recent years, IC cards of the type in which ICs are built in a card are employed, and IC card readers have appeared, in which an IC contact is disposed detachably and attachably to a contact terminal portion of the IC card thereby to perform information read/write.
The IC card reader, which performs the information read/write on the IC card, has a card insertion slot through which a card is inserted in an apparatus mainbody; a card transport path that guides the card inserted through a card insertion slot to a card read/write position; and transport driving means that moves the card in the card transport path. The genuineness or the obverse and reverse sides of the card inserted into the card insertion opening are sensed by an inlet sensor disposed near the card insertion slot. When the card has been sensed to be correct, the card is transported by a transport driving means to an IC contact disposed detachably and attachably to the contact terminal portion of the IC card, whereby performing the information read/write thereon.
For a card reader that performs information recording/reproduction on a magnetic stripe of a magnetic card of the type generally widely used, an inlet sensor of the above-described type can be formed into a simple configuration by using a small magnetic head. However, in the case that an IC card is used as a recent card, no specific proposal has been made regarding how to detect the validity of the IC card.
In the case that an eddy-current type sensor of the type disclosed in Japanese Unexamined Patent Application Publication No. 11-352108 is used to determine an IC card, there is a problem in that thinning of the card is disabled. More specifically, in the case of the eddy-current type sensor, three or more excitation rod-shaped core bodies are disposed, so that enlargement of the apparatus cannot be averted. In addition, the magnetic permeability of the core body varies depending on the humidity thereby to cause the temperature characteristics for the usage environment to significantly vary, so that a reference value level for determining the presence or absence of the IC card should be set higher than the variation in the temperature characteristics. As such, in the case that a predetermined or larger distance occurs between the IC card and the inlet sensor, a case can occur in which detection of the IC card is disabled.
Further, for recent IC-card using card readers of the type described above, a detailed proposal regarding how to detect card types has not been made to date.
As described above, the conventional card reader has problems in that it is incapable of determining the type of a card inserted in the apparatus mainbody; that is, it is incapable of determining whether a card being used at the present time is a magnetic card or an IC card. In addition, in the case of an IC card, the card reader is incapable of determining whether the IC card is a contact IC card or contactless IC card, therefore completely disabling determining a common type of these cards, as a matter of course. As such, when, for example, an unusable card is inserted, the control operation of closing the shutter cannot be securely performed whereby to disable countermeasures to prevent from being erroneous operations, damage, and/or the like of the apparatus.
In addition, the card reader using the IC card, appropriately senses the genuineness or the obverse and reverse sides of the IC card through the inlet sensor. However, in an event that, for example, wire disconnection has occurred inside the inlet sensor or between the inlet sensor and a signal processor circuit or the like, since the IC card cannot be appropriately sensed, there arises a problem in that even a correct IC card is erroneously recognized as being an incorrect card whereby rendering it unusable. Nevertheless, in a general IC-card using card reader, wire disconnection and the like in the inlet sensor cannot be pre-detected.
Accordingly, an object of the present invention is to provide an object sensor designed into a simple configuration and to be capable of obtaining a steady detection result while obtaining favorable detection sensitivity.
Another object of the present invention is to provide an IC card reader designed to have a simple configuration and to be capable of performing an excellent detection of an IC card.
Still another object of the present invention is to provide an IC card reader designed to have a simple, small configuration and to be capable of performing a secure, steady detection of the type of an inserted IC card whereby to enable favorably preventing, for example, erroneous operations and damage.
Yet another object of the present invention is to provide an IC card reader designed to be capable of performing appropriate processing by detecting wire disconnection and the like in an inlet sensor before sensing card genuineness.